In the Sogdian letters, which have been discovered in 1932/33 by Soviet archaeologists on Mount Mug in Tajikistan, there are mentions of payments for different services, usually in drachms (δraxmē). These data are useful to reconstruct the monetary economy of Sogdiana at the dawning of the Arab invasion (beginning of the 8th Century CE).
The present article focuses, in particular, on a peculiar and still puzzling linguistic compound formed by the name ʽdrachmsʼ followed by an adjective, apparently derived from the word dīnār with the suffix -ka. The exact meaning of this unusual expression cannot be ascertained only on philological ground, but it is also necessary to take into consideration the coin circulation of Northern Tokharistan. The author analyzes the typology of the few documents that contain such a compound, “dinaric drachms”, and based on the evidence of local coin hoards, contemporary to the Sogdian letters, suggests that it actually refers to Islamic dirhams or to a standard unit of account of higher value than the Bukhar-khudat silver coins, which circulated abundantly along the Zeravšan Valley.
The arrival of the Arab army in Sogdiana provoked a slow but irreversible introduction of the reformed Islamic coins into the territory; this led, for a certain period, to a double monetary circulation of silver coins with the same nominal value but with different intrinsic content.